Explanation of the author's (may Allah have mercy on him) statement: "… and the verb is identified by qad, the sin, sawfa, and the silent feminine taa …"

The Shaykh : He said: "The verb is identified by qad, the sin, sawfa, and the silent feminine taa". These are four signs. Every word preceded by qad is a verb. Every word preceded by the sin or sawfa is a verb. Every word ending with the silent feminine taa is a verb. Is that clear? Good.
The first example: "Aflaha" (He has succeeded) is a verb; the evidence is the entry of qad. "Al-mu'minun" (The believers) is a noun; the evidence is the entry of alif and lam. Good. It is identified by the sin: "Ya'lamun" (They know) is a verb. What is its sign?
The student: The sin.

The Shaykh : The entry of the sin. Good. In the surah "Al-Haqqah": "Sawfa ta'lamun" (You will know) is a verb; the evidence is the entry of sawfa. So, every word upon which the sin enters is a verb, and every word upon which sawfa enters is a verb. Good. We say every word upon which the sin enters. Pay attention: if the sin is part of the word itself, it is not a verb. It may be a verb, or it may not be. For example, "sihr" (magic). We do not say "sihr" is a verb because it contains the sin. Rather, we say the sin entered it. The sin is not part of its structure; the sin is not part of its structure, but is external to the word's structure. Look at "ya'lamun" (they know). The first part of the verb is "ya'lamun"; the sin is what entered the verb.
And the author (may Allah have mercy on him) said here: "The silent feminine taa". The silent feminine taa. He stipulated two conditions, or rather three conditions: the taa is feminine, and it is silent. He did not say "with the taa"; he said: "The silent feminine taa". So, every word ending with the silent feminine taa is a verb. Every word ending with the silent feminine taa is a verb. He asked, "What do you say about it?"
The student: A verb.

The Shaykh : A verb. Why? Because it ended with the silent feminine taa. Good. "Qalat" (She said) is a verb because it ended with the silent feminine taa. Good.
If the word ended with a taa other than the feminine taa, like "bayt" (house). "Bayt" ends with a taa, but it is not for femininity. Do we say "bayt" is a verb? No. It has a taa at the end, but the taa here is not for femininity; rather, it is part of the word's structure.
Good. The silent feminine taa is specified to exclude the non-silent one. If the feminine taa is not silent, it is not a sign of a verb. You say "shajarah" (tree). "Shajarah": is this taa the feminine taa or not? This is "baqarah" (cow). This is a feminine taa, but is it silent or not silent? Not silent. So, we do not say "shajarah" is a verb. Why did we not say it is a verb? Because the feminine taa is not silent. "Baqarah": we do not say it is a verb. Why? Because the feminine taa is not silent. "Rahmah" (mercy). He said: "Rahmah." Here, is "rahmah" a verb? Why? Because the feminine taa is not silent. Good. So, the verb has four signs: qad, which is at its beginning; the sin and sawfa, which are at its beginning; the feminine taa, which is at its end; and the silent feminine taa, which is at its end. Is that clear, everyone? Good.